Rotor yoke with circumferential recess portions and motor applying rotor yoke

Abstract

A rotor yoke includes plural rotor cores having a disk shape laminated to be formed in a cylindrical shape, plural magnet inserting holes each including a longitudinal side and a transverse side, penetrated in a laminating direction of the rotor yoke, a bridge portion arranged between the magnet inserting holes adjacent to one another in a circumferential direction of the rotor cores and connecting an inner area to an outer area, a recessed portion arranged at the bridge portion and formed from the outer circumferential surface of the rotor cores toward radially inward and a protruding edge protruding toward an inside of the magnet inserting hole.

The invention claimed is: 
     
       1. A rotor yoke, comprising:
 a plurality of rotor cores laminated to be formed in a cylindrical shape, each of the plurality of rotor cores possessing a disk shape; 
 a plurality of magnet inserting holes, each including a longitudinal side and a transverse side arranged on a surface of the rotor cores orthogonal to a rotation shaft, the longitudinal sides of the magnet inserting holes being arranged separately from one another near an outer circumferential surface of the rotor cores along a circumferential direction, the magnet inserting holes penetrating the rotor yoke in a laminating direction of the rotor yoke; 
 a bridge portion arranged between two of the magnet inserting holes that are adjacent to one another in a circumferential direction of the rotor cores, the bridge portion connecting an inner area arranged radially inward of the magnet inserting holes to an outer area arranged radially outward of the magnet inserting holes; 
 a recessed portion arranged at the bridge portion and formed from the outer circumferential surface of the rotor cores toward a radially inward direction; 
 a protruding edge of one of the magnet inserting holes being arranged at the bridge portion and protruding toward an inside of the one magnet inserting hole, the protruding edge including a most protruding edge at a portion of the transverse side of the one magnet inserting hole; and 
 the protruding edge forming first and second clearance portions when a magnet is located in the one magnet inserting hole, the first clearance portion being formed by one end of the transverse side of the one magnet inserting hole and being recessed toward an outside of the one magnet inserting hole, and the second clearance portion being formed by another end of the transverse side of the one magnet inserting hole and being recessed toward the outside of the one of the magnet inserting holes. 
 
     
     
       2. The rotor yoke according to  claim 1 , wherein the recessed portion has an arc shape arranged on the surface of the rotor cores orthogonal to the rotation shaft. 
     
     
       3. The rotor yoke according to  claim 1 , wherein the bridge portion includes a first bridge portion and a second bridge portion, the outer area is one of a plurality of outer areas, the first bridge portion is formed to connect adjacent ones of the plurality of the outer areas adjacent to one another, and a second bridge portion is formed to connect the first bridge portion to the inner area, wherein, at least one of widths of the first bridge portion and the second bridge portion arranged on the surface of the rotor cores orthogonal to the rotation shaft is equal to a plate-thickness of the rotor cores. 
     
     
       4. The rotor yoke according to  claim 1 , wherein at least one of the bridge portions is removed and the magnet inserting hole communicates with the recessed portion at a part or all of the laminated rotor cores. 
     
     
       5. The rotor yoke according to  claim 4 , wherein the bridge portion is alternately removed in a circumferential direction from all the rotor cores except for the rotor cores arranged at opposite end sides, and a clearance provided by removing the bridge portion and the bridge portion adjacent to one another are arranged to be overlapped in the laminating direction to form the rotor yoke. 
     
     
       6. The rotor yoke according to  claim 3 , wherein at least a portion of the first bridge portion is removed and the magnet inserting hole communicates with the recessed portion at a part or all of the laminated rotor cores while the second bridge portion, instead of being removed, connects to a residual portion of the first bridge portion. 
     
     
       7. The rotor yoke according to  claim 6 , wherein, except for the rotor cores arranged at opposite end sides, in a view seen along the laminating direction, a first rotor core, by removing a part of the first bridge portion, includes the first bridge portion connecting to one of the outer areas arranged at opposite sides of the first bridge portion and to the second bridge portion, and not connecting to the other outer areas, and a second rotor core, by removing a part of the first bridge portion, includes the first bridge portion connecting to the other outer areas arranged at the opposite sides of the first bridge portion and to the second bridge portion, and not connecting to said one of the outer areas, and wherein the first rotor core and the second rotor core are laminated alternately to form the rotor yoke. 
     
     
       8. A motor, comprising:
 a rotor yoke including 
 a plurality of rotor cores laminated to be formed in a cylindrical shape, each of the plurality of rotor cores possessing a disk shape; 
 a plurality of magnet inserting holes, each including a longitudinal side and a transverse side arranged on a surface of the rotor cores orthogonal to a rotation shaft, the longitudinal sides of the magnet inserting holes being arranged separately from one another near an outer circumferential surface of the rotor cores along a circumferential direction, the magnet inserting holes penetrating the rotor yoke in a laminating direction of the rotor yoke; 
 a bridge portion arranged between two of the magnet inserting holes that are adjacent to one another in a circumferential direction of the rotor cores, the bridge portion connecting an inner area arranged radially inward of the magnet inserting holes to an outer area arranged radially outward of the magnet inserting holes; 
 a recessed portion arranged at the bridge portion and formed from the outer circumferential surface of the rotor cores toward a radially inward direction; 
 a protruding edge of one of the magnet inserting holes being arranged at the bridge portion and protruding toward an inside of the one magnet inserting hole, the protruding edge including a most protruding edge at a portion of the transverse side of the one magnet inserting hole; and 
 the protruding edge forming first and second clearance portions when a magnet is located in the one magnet inserting hole, the first clearance portion being formed by one end of the transverse side of the one magnet inserting hole and being recessed toward an outside of the one magnet inserting hole, and the second clearance portion being formed by another end of the transverse side of the one magnet inserting hole and being recessed toward the outside of the one of the magnet inserting holes. 
 
     
     
       9. The motor according to  claim 8 , wherein the recessed portion has an arc shape arranged on the surface of the rotor cores orthogonal to the rotation shaft. 
     
     
       10. The motor according to  claim 8 , wherein the bridge portion includes a first bridge portion and a second bridge portion, the outer area is one of a plurality of outer areas, the first bridge portion is formed to connect adjacent ones of the plurality of the outer areas adjacent to one another, and a second bridge portion is formed to connect the first bridge portion to the inner area, wherein, at least one of widths of the first bridge portion and the second bridge portion arranged on the surface of the rotor cores orthogonal to the rotation shaft is equal to a plate-thickness of the rotor cores. 
     
     
       11. The motor according to  claim 8 , wherein at least one of the bridge portions is removed and the magnet inserting hole communicates with the recessed portion at a part or all of the laminated rotor cores. 
     
     
       12. The motor according to  claim 8 , wherein the bridge portion is alternately removed in a circumferential direction from all the rotor cores except for the rotor cores arranged at opposite end sides, and a clearance provided by removing the bridge portion and the bridge portion adjacent to one another are arranged to be overlapped in the laminating direction to form the rotor yoke. 
     
     
       13. The motor according to  claim 8 , wherein at least a portion of the first bridge portion is removed and the magnet inserting hole communicates with the recessed portion at a part or all of the laminated rotor cores while the second bridge portion, instead of being removed, connects to a residual portion of the first bridge portion. 
     
     
       14. The motor according to  claim 8 , wherein, except for the rotor cores arranged at opposite end sides, in a view seen along the laminating direction, a first rotor core, by removing a part of the first bridge portion, includes the first bridge portion connecting to one of the outer areas arranged at opposite sides of the first bridge portion and to the second bridge portion, and not connecting to the other outer areas, and a second rotor core, by removing a part of the first bridge portion, includes the first bridge portion connecting to the other outer areas arranged at the opposite sides of the first bridge portion and to the second bridge portion, and not connecting to said one of the outer areas, and wherein the first rotor core and the second rotor core are laminated alternately to form the rotor yoke. 
     
     
       15. A rotor yoke, comprising:
 a plurality of rotor cores laminated to form a cylindrical shape, each of the plurality of rotor cores possessing a disk shape; 
 a plurality of magnet inserting holes passing through each of the rotor cores, each magnet insertion hole including a longitudinal side and first and second transverse sides arranged on a surface of the rotor cores orthogonal to a rotation shaft, the longitudinal sides of the magnet inserting holes being arranged separately from one another near an outer circumferential surface of the rotor cores along a circumferential direction, the magnet inserting holes penetrating respective ones of the rotor cores in a laminating direction of the rotor yoke; 
 a bridge portion between two of the magnet inserting holes that are adjacent to one another in a circumferential direction of each rotor core, the bridge portion connecting an inner area arranged radially inward of the magnet inserting holes to an outer area arranged radially outward of the magnet inserting holes; 
 a recessed portion arranged at the bridge portion and formed from the outer circumferential surface of the rotor cores toward a radially inward direction; 
 the magnet inserting holes being shaped and arranged such that when a magnet possessing a rectangular cross section is located in a respective one of the magnet inserting holes, the magnet possessing a first shorter side between two first corners of the rectangular cross section and a second shorter side between two second corners of the rectangular cross section, the first shorter side of the magnet contacts the first transverse side, the second shorter side of the magnet contacts the second transverse side, and the two first corners of the magnet are spaced from the first transverse side. 
 
     
     
       16. The rotor yoke according to  claim 15 , wherein two second corners of the magnet are spaced from the second transverse side. 
     
     
       17. The rotor yoke according to  claim 15 , wherein the recessed portion has an arc shape arranged on the surface of the rotor cores orthogonal to the rotation shaft. 
     
     
       18. The rotor yoke according to  claim 15 , wherein the bridge portion includes a first bridge portion and a second bridge portion, the outer area is one of a plurality of outer areas, the first bridge portion being formed to connect adjacent ones of the plurality of the outer areas to one another, and a second bridge portion is formed to connect the first bridge portion to the inner area, wherein at least one of widths of the first bridge portion and the second bridge portion arranged on the surface of the rotor cores orthogonal to the rotation shaft is equal to a plate-thickness of the rotor cores.